Electric pump-governor.



ELM', P. MURPHR ELECTRIC PUMP GOVERNUR.

IWFLIUATION FILED FBIB.25, 1907K azmf Aug y' 3 SHEETS-SHEET awww Awy.

E. MAn 13 MURPHY, ELECTRIC PUMP GOVERNOR.

APILIGATION FILED EB.25, 190?.

Patented Aug. 272 1912.

3 SHEETS-SHEET 2.

/WTHHSSES INVENTOR i ,f/ MWL/MM .V M H, 7 j

H. M. P. MURPHY. ELECTRIC PUMP GOVERNOR.

APPLICATION FILED FEB.25,1907.

33,886. Patented Aug. 2'?. 1912.

3 SHEETS-SHEET 3.

. i o all whom t may concern:

. sTATEs PATENT OFFICE.

vHOWARD M. P. MURPHY, OF PITTSBURGH, PENNSYLVANIA, yASSIGNOR TO THEWEST- INGI-IOUSE AIR BRAKE COMPANY, F PITTSBURGH, PENNSYLVANIA, ACORPORA- TION QF PENNSYLVANIA.

ELECTRIC PUMP-GOVERNOR.

' Be it known that I, HOWARD M. P. Mim- PHY, a citizen of the UnitedStates, residing at Pittsburgh, in the county of Allegheny and State ofPennsylvania, have invented new and. useful Improvements in ElectricPump-Governors, ot'which the following is a specification.

This invention relates to pump governors, and more particularly togovernors for electric motor drivenv pumps, wherein the main controllingdevice, or switch, for opening and closing the circuit to the motor fordriving the pump is operated according to the pressure produced by thepump.

The principal object of my present invention is to simplify `theconstruction of pressure governors of this class, wherein a mainactuating piston is employed for throwing the contro-lling device, orswitch, to its ditferent positions, for cutting the pump into -or out ofoperation; 'and having means subject to the pump pressure forcontrolling the supply ot fluid to and its release from the actuatingpiston.

Another ,object is to provide improved means, whereby the movementof theactuating piston from one position to the other shall be eiected with aquick, positive and snap-like action, to causeV a rapid and suddenshitting of the controlling device, or switch.

Another object is to provide means whereby the movement of the actuatingpiston from its outer position may control the release of fluid from theface ot the piston andA cause a rapid return movement.

Another object is to provide improved means, governed by the pumppressure, for rapidly supplying a large volume of fluid to the actuatingpiston.

Another object is to provide an improved adjustable spring mechanismopposing the pump pressure, whereby the governor may be' readily set toany desired pressure. and the range or difference between the cutting inandthe cutting out press-ures may be quickly adjusted to meet anydesired conditions.

Another object is to provide improved mechanism tor controlling thegovernor by 'diiiereutial fluid pressures.

These objects, as well as others, arcat- Specification of LettersPatent.

Application filed February 25, 1907.

'which-- Patented Aug. 27, 191.2. serial No. 359,241;

tained by means'of the apparatus which will now bemore fully describedin connection with the accompanying drawings, in

Figure 1 is a vertical sectional view of one form of governing deviceembodying my improvements; Fig. Q a similar sectional view, showing amodication adapted to be operated by diiierential pressures; Fig. 3 asimilarsectional view showing a modification in which the two valvepistons have similar under differential fluid pressures; Fig. 5 asectional view showing still another modiiication embodying a diaphragmand valve, the lower part of thespring box being broken away; Figy 6 asimilar sectional viewwitli additional mechanism .for operating thegovernor undertwoditlerent lluid pressures; Figs. 7, S and 9 views ofthe slide valve and seat of the construction shown in Fig. 5; and Figs.1Q, 11 and 12 corresponding views'of the slide valve andV seat of thegovernor construction shown in Fig.- 6.

According to the construction sho-wn in Fig. '1, the main `controllingdevice, or switch, 1, is connected to the actuating piston, 2, which isnormally lield at its inner position in the cylinder 3 by means of thespring Ll.

Pressure from the pump or reservoir is admitted by pipe 5 to the valvepiston 6, which is normally held to its seat by the adjustable spring 8,sbA that only7 a small area ot the piston 6 is then subject to thereservoir pressure. A port 9 leads from the space outside of this valveseat to the valve piston 12, which controls port 13 leading t-o the faceof actuating piston 2 in cylinder 3. A by-pass groove 10 may be providedaround piston 6, and a port 11 leads from the space below the piston tothe port 14, which communicates with the cylinder 3 near its outer end.A

The valve piston .12 has a rib, or seat` l5,

-- which is adapted to engage gasket 16 in one position and cut offcommunication from po-rt 14 to the one side of said piston within theseat portion, while the stem 17 is provided with a small groove 18forming a rcstricted passage from this space beneath valve piston to thespring chamber and cutlet port 20. The adjustable spring 19 determinesthe .point at which the governor cuts in.

When the actuating piston 2 is at its outer position it engages the seat21 for making a tight joint, and it desired, a small port 23 may beprovided for maintaining the pressure upon the actuating piston. thisport being closed by the piston when in its inner position. The maincontrolling 'device, or switch mechanism, may be covered by a casing,22.

In the normal position of the parts of the governor, as shown in thedrawings, the main switch is closed and the pump is operating to raisethe fluid pressure in the reservoir and through pipe 5 on the small areaof vvalve piston 6, the spring. S beingfadjusted to the maximum degreeof pressure at which it is desired that the pump shall cut out. When thepump pressure reaches this degree the'valve piston 6 is forcedslightlyaway from its seat 7 ,y thereby permitting the pressure to act upon thegreater area of the face of the piston and move the, same quicklydownward, and opening the supply of iuid through port 9 to valve pis#ton .12. rIvhe equalizing groove V10 is closed by the first part of thedownward movement of the piston 6 and the space beneath said piston, andalso beneath the valve piston 12 has a free exhaust through the largepassage 14 and outlet port 211, so thatk the pressure then acting on theupper face of piston 12 moves the same rapidly downward against its seaton gasket 16 compressing the spring '19 and opening the port 13 tosupply luidunder pressure to the cylinder 3 when it acts upon the piston2 to throw the same quickly to its out-er position. This movement of theactuating piston closes the exhaust through the passage 14E and shiftsthe main controlling switch to its open pof sition to cut the pump outof operation. The actuating piston is then held tightly against its seat21 and the pressure equalizing through passages 14 and 11 upon thepiston 6 allows the'spring 8 to return the same to its seat 7. As thegroove 1S in stem 17 maintains atmospheric pressure beneath piston 12the parts remain in this position until the pump pressure hasldiminished to the point at which the spring 19 overcomes the fluidpressure acting on piston 12, at which time the seat 15 is slightlyraised :trom the gasket 16. The iuid. pressures acting on opposite sidesof the valve piston 12 are then immediately balanced, by theequalization of the reservoir pressure from the cylinder 3 throughpassages 13 and 14:, as restricted groove 1S is too small to permit `theescape of considerable volume of fluid, and the spring 19 returns thepiston valve 12 rapidly toits inner position, thereby openingcommunication between ports 14 and 13. As the pressurel acting onv thepiston 2 in cylinder 3 begins to fall, due to the escape of fluidthrough groove 18 and outlet port 20, the spring 1 moves the piston 2away'trom its seat 21 and thereby opens a large by-pass and exhaustpassage from the face of the actuating piston through ports'13 and 14:and outlet port 2&1-- to the atmosphere'. to return the piston 2 to itsinner position and to throw the controlling device to its closedposition with a quick, positive and snap-like action, thereby againcutting in the pump.

The ports 13 and 14 are ot large capacity,

vin order to permit the supply or release of a large volume of` fluidquickly to or from.

the cylinder 3 and thereby effect a sudden The spring then acts andpositive movement 'of the piston and controlling switch from oneposition to the other. y f o The range of the governor, or the dierencebetween the cutting in and cutting out pressure may be made anythingdesired by the adjustment of the springs 8 and 19.

During the time that' the pump is cut out, and afterthe'valve piston6.has returned to its seat, the pressure upon the actuating piston 2 andthe valve piston 12 is maintained by the feed through the small port 23.l x

The modified construction shown in Fig.

2 is, substantially the same as that of Fig. 1

except that the valve pistons are arranged to operate horizontallyinstead of vertically,A and the valve piston 12 is provided with anadditional small seat 25 for controlling the supply of fluid fromthereservoir connec tion 5 through ports 26 and 13 to maintain thepressure instead of the small port 23 illustrated in Fig.. 1. i Fig. 2also illustrates an additional feature of my improvement, comprising anabutment, or diaphragm, 30, subject on one side to the reservoirpressure in chamber 28 and on the other side, in chamber 29, to thepressure of another source, such as a reservoir pipe line 34, which maybe employed tor connecting several reservoirs where each reservoiris'provided with a pump for furnishing compressed fluid thereto, and itis desirable that all of the pumps should operate together to raise thepressure in thel sys tem to its maximum cutting out point. The stems ofthe valve pistons 6 and 12 are ex tended through close fitting guidesinto a small chamber 27, from which leads a port 31, and the vdiaphragm30 is provided with` va valve 33 for controlling communication from port31 to port 32 and the atmosphere. Spring 35 normally holds the valve 33closed. The operation of this form of my improvement, when used with asingle pump and reservoir, will now be readily understood. from theforegoing description.

Whenemployed in connection with a plurality of pumps and reservoirsconnected by a. reservoir pipe line, each pump and reservoir beingprovided with a governor, it is diilicult to adjust all the governors tocut in at exactly the same degree of pressure; but

with my imprb-ved differential pressure at-' of the governors raises thevalve 83 and vents the pressure in chamber 27 on the valve stem totheatmosphere, thereby assisting thecutting in spring 19 acting onthe-valve piston 124 sutliciently to operate the governor to cut inthepump. In the same manner each p ump will be cut in by lts governorimmediately after any other one of the governors cuts in, and all of the'pumps will assist in raising the pressure of embodiment of my inventionas illustrated l ber 26, 1910.

According to the modilication shown in Figs. 3 and 4, the structure issimplified by i combining the two valve pistons, 6 and 1Q,

`into one valve piston, 12, adapted to cngage the seat 7 with the smallarea of its upper surface subject to the reservoir pressure, and havingseat 15 upon its opposite side for engaging gasket 16 when moved to theother position, In this case, the cutting cut pressure is determined bythe adjustable spring 8 alone, since this spring exerts itsV force inopposition to the iiuid pressure acting upon the small area ofthe valvepiston within the seat 7, while the cuttingin pressure is determined bythe combined force of the two springs 8 and 36, which is exerted inopposition to the fluid pressure acting upon the valve piston of thearea within the seat 15 when the same is seated against the gasket 16./The restricted passage from the space beneath the valve piston to theoutlet port Q0 may be formed by making the stem 17 with a loose fit, asindicated in Figs. 3 and 4., or with grooves, as

shown in Figs. 1 and 2. The stemll? is of such length as to be freefrom, the supplemental spring 36 when the piston va'lve is in its upperposition, but is adapted te engage and compress said spring uponthemovement of the piston to its opposite position,

and the range of the governor may be readily' adjusted, as desired, byvarying the tension of they spring 36. The operation of thisI form of myimprovement will now be readily understood.

When the pump pressure acting on the I small area of piston 12, withinthe seat 7, overcomes the pressure of spring 8, the valve is forcedslightly from its seat and exposes' the full area of the piston to thereservoir pressure, which instantly carries the seatI 15 against the.gasket 16, compressing both springs 8 and 86, and opening the large port13 to supply Huid in a large volume to cylinder 3 to throw the actuatingpiston 2 and controlling switch with a` quick and positive movement tothe open position. The pistou 2 is then held against seat 21 by thereservoir pressure, which also fills the passage 14 and space around theflange 15 o valve piston 12, but cannot escape through the restrictedpassage to outlet port 20. Then the pressure acting on the face of thevalve piston diminishes to a point less than the combined force ofsprings 8 and 36, the seat 15 will be moved away from the gasket andpermit an immediate equalization of fluid pressure upon opposite sidesof said piston, sothat the spring 8 instantly returns the same to itsposition against the seat '7, at the same time allowing the discharge offiuid from the actuating cylinder through the restricted outlet and'port 20 to the atmosphere. As the pressure diminishes on piston 2,'thespring i starts the saine away from its seat 21, and as piston passesthe port 14 it opens a large passage for therelease of fluid from theface of the piston around through ports 13 and 1st to the atmosphere,whereupon the spring 4c operates to return the piston and through thecontrolling switch to its closed position with a rapid and positivemovement.

The additional di'lferent-ial pressure attachment shown in Fig. 4;operates substantially like that described in connection with Fig. 2,except that the diaphragm valve 33 controls the supply of fluid underpressure from the pipe line 34 througl-l the port 31 to the springchamber at one end of the stem of the valve piston, instead ofreleasing' pressure from the opposite end of said stem, the result beingthe same in either case.

In both of these modifications, it will be noticed that the differentialpressure mechanism operates to cause t-he governor to eut 1in only whenthe pump pressure is nearly downto the cutting in point. Wlien theincreased nearly -to the cutting out point, if

the pressure upon the end of the stem of the valve piston, but thiswould not cause any movement of the said piston, as the reservoirpressure 1s then acting u-pon the large area to hold the piston seatedon the gasket 16.

The slight additional pressure applied at the end of the stem is nottherefore suliicient at this time to cause the governor to cut 1n again,consequently each governor will op? erate independently to cut out itspump, as before described.

According to the modification illustrated. in Figs. 5 to 12 of thedrawings, the movable abutment subject to the pump pressure, is shown ascomprising a diaphragm 37 having a slide valve 33-with portsforcontrolling the passages 13'and 14 and the supply of fiuid to and itsrelease 'from the cylinder 3 of the actuatingpiston2. The fluid 25pressure acting on the' diaphragm 37 is opposed by a main spring 43` inchamber 52 and the diaphragm stem 44 is adapted -to engage an additionalspring 45 upon a short outward movement of said stem, although the sameis no-rmally free from engagement with said additional spring when inthe position shown in Figs. 5-and 6 of the drawings. The valve seat isprovided with a port 39 leading` to thecyli'nder 3, where it is normallyclosed by valve 46 carried by piston 2, and a port 40 leading to theatmosphere, while the valve 38 has a through port 41 and a ycavity 42,with eX- tension 47. The operation of this modified form of myimprovement is as follows The springs being adjusted to the desiredpressures, the parts normally occupy the po-.

sit-ions shown in Figs. 5 and 6, with the coi-- trolling switch closedandthe pump in operation; when the pump pressure on the diaphragm 37increases to such a pointias to compress the spring 43,the diaphragm andslide valve movefdownward'until the stem 44 engages the additionalspring 45, but this movement is not suflicient to connect the throughport 41 of the valve with theport 13 in the seat, although it doesopenthe port 39 and closes communication between the exhaust. port 40 andthe extension 47 of the cavity 42. It is therefore necessary for thefluid pressure to rise to such a point as to compress both springs 43and 45, in order to bring port `41` over port 13, as indicated in Figs.7 and 10, and supply fluidl to operate the piston 2, for, althoughtheport 39 was previously opened, the pressure of the spring 4 holdingvalve 46 to its seat, yprevents the admission of fluid through port 39to cylinder 3 until the piston 2 moves .outward and 65 carriesvalve 46away from its seat. As

large port 39 to supply air to the actuating soon as the piston 2 startsoutward under the pressure admitted through ports 41 and 13, the valve46 opens the large port 39 for supplying alarge volume of fluid rapidlyto the cylinder' 3, thereby elfecting a quicio and 70 positive'outwardmovement of the piston against the spring 4, and throwing the-controlling switch to its open position. The piston 2 isjthen held'against its seat 21 by the fluid pressure. Y

It should lbe understood that 1 do not claim as my invention thefeature, described in connection with the modification shown i-n Figs. 5to 12 inclusive, of providing a piston in large volume upon upwardmovement thereof, this feature being the invention of W. V` Turner andthe subject-matter of Patent No. 950,737, issued March 1, 1910. As thepump pressure acting on dia,- phragm 37 diminishes, the combined forcesof the springs 43. and 45 operate to move the valve upward until thestem 44 is just free from engagement with spring 45 and the port 13 islclcsed. The spring 43'then acts 90 alone against the fluid pressure uponthe diaphragm, and as this pressure continues to fall the single springmoves the valve to its upper position, as indicated in Fig. 5, in whichthe port 39 is. closed and the cavity 42 connects ports 13 and 14, whilethe eXtension 4i communicates, with the exhaust port 40 and permits thedischarge from the cylinder 3 through ports 13, 47 and 40 to theatmosphere. I

As the pressure is reduced o n the face of the pistony 2, the spring 4moves the piston away from its seat 21 and opens the port14 to the spacebehindthe piston and to the atmosphere, and as ports 13 and 14 are thencon- 105 nected through cavity42 a large passage is provided for therapid exhaust of fluid from the cylinder 3 upon the face of the piston2. The actuating piston is therefore returned to its inner position witha rapid and posi- 11()` tive movement, thereby closing the controllingswitch and cut-ting in the pump. In this manner the movement of theactuating piston serves lto control the supply and the l release of Huidto and from thelcylinder, whereby a more rapid and sudden action issecured in shifting the controlling switch from one position to theother.

The spring 43 is adjusted to the desired minimum degree of pumppressure, since the spring by itself determines the point at which'thegovernor is to` cut in, while the combined force of the springs 43 and45 determines the desired maximum degree of pressure at which thegovernor cuts out the pump, but the range, or difference between thesepressures,l may be readily varied to suit any given condition by merelvadjust-- ing the tension of the. additional spring 45.

The differential pressure attachment 13o similar manner to` thatdescribed in connection with Fig. 4, except thatl the diaphragm valve 33controls the supply of Huid under pressure from the reservoir throughports 48 and 49 to the chamber 52 beneath the main diaphragmBT forassisting the spring 43 to move the slide valve to its cutting inposition. j

lt will be noticed that the ports 48 and 49 are connected by the cavity50 only when the valveis at or near its cutting in position, while thiscommunication is cut off when the valve is in the opposite position, asindicated lin Fig. l0. By this means the differential pressure mechanismcan operate to cause a governor to eut in only when the pressure is lowand the governor is near to its cutting in point, but will Ahave noeifect upon the governor after the pressure has increased toward themaximum sufiiciently to move the valve to disconnect the ports 4S and49.

. mentto operate the controlling switch with a quick, snap-like action;also at the time of cutting in, that the preliminary inward' movement ofthe actuating piston operates kto control the pressure intits cylinderby opening a large exhaust passage for the escape of fluid from thefaceyof said piston and thereby permits the spring to throwthe piston'and controlling switch' to the other position with a quick andpositivemovement.

shown iii-Fig. 3, has the further advantage of being extremely simple instructure, 'hav-v ingy but a single movable abutment or valve pistonwith two springs, for controlling the supply of fluid to and its releasefrom the cylinder of the actuating piston, which structure is found tobe very durable and reliable in its operationin actual practice.

Having new described my invention, what l claim as new, and desire tosecure by Letters atent, is :M

l. A pump governor comprising` a pump controlling device, an actuatingpiston therefor., a valve piston for controlling the fluid pressure onsaid actuating piston having a s t and subject inthe seated position topu mp pressure in one direction and in the i. osite direction to thepressure of an ad- The preferred form,` of construction, as`

justable spring and a `chamber having a restricted exhaust port, andmeans adapted 2. A pump governor comprising a pump controlling device,an actuating piston theretor, a valve piston for supplying and releasingfluid to and from said piston to operate the same having aseatedposition and subject to pump pressure in one direction and in theopposite direction to spring pressure and the pressure of a chamberhaving a restricted exhaust port, the preliminary movement of saidnvalve piston from its seated position being adapted to admit fluid tosaid chamber to acceleratethe movement thereof, and means adapted inanother position of the valve piston to open a larve port for permittingthe free exhaust of air leaking into said chamber.

8. A pump governor comprising a pump controlling device, an actuatingpiston therefor, a valve piston mechanism for varying the Iiuid pressureon said actuating piston and subject on one side to pump pressuretending to move same to one position and on the opposite side to springpressure and the pressure of a chamber having restricted exhaust p ortand tending to move the same to the opposite position, the preliminarymovement of said valve piston mechanism from the first position beingadapted to admit fluid to said chamber to effect the positive movementthereof and the preliminary movement from the second position beingadapted to expose a larger area of same to pump pressure to facilitatethe quick movement thereof, and means for opening' a vent port to said`chamber in the ,last mentioned position to permit the free exhaust offluid leaking into said chamber.

4. A pump governor comprising a pump controlling device, a piston foractuating same, a valve piston mechanismY subject to spring pressure onone side and to pump pressure on the opposite side for controlling thesupply andrelease of fluid to and from said actuating piston and havinga seat in one direction exposing a small area thereof to pump pressureand the remaining area to atmospheric pressure through a restricted portand a seat in the opposite direction exposinga portion of the areathereof to atmospheric pressure through a restricted port.

5. A pump governor comprising a pump controlling device, a piston foractuating same, a valve piston mechanism subject to pump pressure forcontrolling the pressure on said actuating piston, a spring for opposingthe pump pressure on said valve piston mechanism toV determine thecutting outpoint and an additional spring adapted to act With the outerspring to determine the from another position, for controlling thekadmission and release of fluid to and from said cylinder.

v. 7. A pump governor comprising a pump controlling device,'a piston andcylinder for actuating saine, and a valve piston mechanism forcontrolling the fluid pressure to operate said piston subject in onedirection to pump pressure and in the opposite direction to one degreeof spring resistance in the "movement from one position, and to' anotherdegree of spring resistance inthe movement from another position, forgoverning the operating fluid pressure in said cylinder.

8. A pump governor comprising a pump controlling device, a piston andcylinder for actuating saine, and 'a valve piston mechanism forcontrolling the fluid pressure to operate said piston subject in onedirection to pump pressure and in the opposite direction to theresistance of tvvo adjustable springs when -in one position and to theresistance of one of said adjustable springs When in-another position.

9. A pressure governor for pumps comprising a pump controlling device, apistonl for operating same, a movable valve piston device adapted toseat in opposite directions and subject on one side to pump pressure forcontrolling the fluid pressure for .operating said piston, an adjustablespring for opposing the pump pressure on said valve piston device and asecond adjustable spring adapted to act on said valve piston device uponmovement from one seat.

10. A pump governor comprising a controlling device, a piston foractuating same, a valve piston having a small area subject to pumppressure When seated in one position, a, spring for opposing the pumppres-A sure on said valve piston, said valve piston being adapted toexpose a larger area to fluid pressure upon movement away from its seat,and means for maintaining the larger area at` atmospheric pressure Whenthe valve piston is on its seat.

11. A pump governor, comprising a main controlling device, a piston foractuating the Y saine, mechanism subject to the pump pressure forsupplying and releasing fluid to and from the actuating piston, andmeans governed by the movement of said actuatof said piston.

13.y A pump governor, comprising a main controlling device, a piston foractuating the same, a valve piste-n adapted to be seated in one positionby the pump pressure and to control 4the release of fluid from the actuating piston, and means for effecting a quick return movement of saidvalve piston as it moves away from its seat. c

14. A pump governor, comprising a main controlling device, a pistonoperated by fluid under pressure for actuating the same, a valvemechanism subject to the opposing forces of the pump pressure and anadjustable spring for controlling the release of fluid from saidactuating piston, and means governed bythe movementI of said piston forfurther controlling the release of fluid therefrom.

15. A pump' governor comprising a main controlling device, a piston foractuating the same, a valve piston subject to the opposing pressures ofthe 'pump and a spring -t'or controlling the supply and release of fluidto and from said actuating piston, said valve piston having oppositevseated positions and being adapted to expose different, p

restricted areas to the pump pressure in said opposite positions.

'16. A pump governor, comprising` a main controlling device, a cylinderand piston for actuating the same, means for supplying fluid to andreleasing it from said cylinder, and a release passage communicatingwith said cylinder near its outer end andadaptcd to be openedby thepreliminary movement of said piston from its outer position.

17. A pump governor, comprising a main controlling device, a cylinderand piston for' actuating the same, a release passage leading from theinner end of Said cylinder to a point near its outer end and adapted tobe opened by the preliminary movement of the piston from its outerposit-ion, and a valve mechanism operating in response to variations iiithe pump pressure for also controlling said release passa-ge.v

18'. A pump governor, comprising a main controlling device, a cylinderand p istoii for actuating the same, a valve piston subject to the pumppressure for controlling the pressure in said cylinder and having a seatin one position, and means for balancing the fluid pressures upon saidpiston when it moves away from this position.

19. A pump governor, comprising a main controlling device, a cylinderand piston for pressure in said cylinder and'having a seat,

in one position, a restricted discharge out- 'let from the seat side ofsaid piston, and

means for opening` communication from the actuating cylinder to saidscat side of t-he valve piston when said valve piston moves to itsopposite position.

20. A pump governor, comprising a main controlling device, a cylinderand piston for actuating' the same, a movable abutment subjectto thepump pressure for controlling the pressure in said cylinder, a springconstantly acting on said abutment in opposition to the pump pressure,and an additional spring adapted to act upon said abutment in oneposition only.

21. A pump governor, comprising a main controlling device, a -cylinderand piston for actuating the same, a. valve piston for controlling thepressure in said cylinder and having differential areas subject to thepump pressure in its different positions, a spring acting in oppositionto the pump pressure to determine the cutting out point, and anadditional spring acting in conjunction with the other spring todetermine the cuttingin point.

22. A pump governor, comprising a main controlling device, a piston foractuating the same, a'valve piston mechanism operated by the pumppressure on one side for supplying fluid to said actuating piston, afree exhaust passage leading from the other side of said valve piston,and means 'for controlling said exhaust passage by the movement of theactuating piston.

23.v A pump governor, comprising a main controlling device, a cylinderand piston for actuating the same, a valve mechanism subject to theopposing forces of the pump pressure and a spring for controlling therelease of fluid from said cylinder to cut in the pump, and adifferential pressure mechanism subject to two opposing fluid pressuresfor assisting the spring to cut the governor in only when the pumppressure is nearly at the cutting .in point.

Q4. A pump governor, comprising a main controlling device, a cylinderand piston for actuating the same, a valve mechanism subject to theopposing forces of the pump pressure and a spring for controlling therelease of fluidy from said cylinder to out in the pump, and aldieren'tial pressure mechanism having a diaphragm subject t0 twoopposing fluid pressures and a valve operated thereby for controlling afluid pressure, to cause the governor to cut in only when the pumppressure is nearly at the cuttingv in point.

25. In a pump governor, the combination, with a main controlling deviceand a cylinder and piston for actuating the same, of a valve pistonsubject to the opposin@r forces of the pump pressure and a spring orcontrolling the pressure in said cylinder, and a differential pressuremechanism having an abutment and valve operated by opposing fluidpressures to supply fluid to act upon the stem of the valve piston andassist the spring to move said valve to its cutting in position.

26. A pressure governor comprising a controlling device, an actuatingpiston therefor, valve means governed. by the pump pressure forsupplying fluid to operate said piston, and means operated by themovement of the piston for varying the pressure on one side thereof, tocause the quick movement of same.

27. A pressure governor comprising a controlling device, an actuatingpiston therefor, valve means governed by the pump pressure for supplyingfluid to operate said piston, and means operated by the movement of thepiston to cause the pump to cutv in, for varying the pressure on oneside of the piston to cause the sudden movement thereof.

28. A pressure governor comprising a controlling device, an actuatingpiston therefor, `valve means governed by the pump pressure forsupplying fluid to operate said piston, and. means operating upon theinitial movementof the piston in the direction to cause the pump tocut'in, for venting` fluid from one side of the piston to thereby effectthe sudden movement thereof.

In testimony whereof I have hereunto set my hand.

HOVARD M. P. MURPHY.

llf'itnesses R. F. EMnRY, J. B. MACDONALD.

esl

